Ferroelectric thin films for memory and MEMS applications require noble metal or refractory metal oxide electrodes. In this paper, physical and chemical parameters during etching of RuO2 and Pr by a dual frequency ECR/RF reactor have been investigated. The removal characteristics of blanket films and films with a patterned mask (photoresist or SiO2 masks) were investigated as a function of gas chemistry (Ar, O-2, halogen gases), ion beam energy (ion extraction/acceleration voltages), substrate bias RF power and working pressure (from 5 x 10(-3) to 5 x 10(-1) Pa). The etch processes were characterized in terms of etch rate, selectivity, critical dimension, lateral uniformity and mask stability. High etching rate processes (up to 70 nm/min for RuO2 and 60 nm/min for Pt with removable photoresist mask) were obtained and a micron scale patterns demonstrated. Patterning of a multilayer stack PZT/Pt/SiO2 could be achieved with a single photolithography step. (C) 2000 Elsevier Science Ltd. All rights reserved.